Dating errors in high-resolution stratigraphy: A detailed X-ray radiograph and AMS-14C study of Zoophycos burrows
Journal
Marine Geology
Journal Volume
177
Journal Issue
3-4
Pages
191-198
Date Issued
2001
Author(s)
Friedrich Werner
Abstract
Bioturbation in oxic deep-sea settings is often considered (if considered at all) to consist of a 2-10 cm thick homogenized layer and some easily recognizable distinct burrows which could be avoided when sub-sampling the sediment cores. However, there is one trace that is often difficult to discern in unlithified sediments, that manifests transport of considerable amounts of sediment over large vertical distances, and that is widely spread in deep-sea sediments in all oceans. This trace, Zoophycos, is therefore predestined to cause errors and even age reversals in high-resolution dating. In order to better estimate the size of these age errors, we have performed AMS-14C dating of the trace itself and of directly surrounding material in two gravity cores from the Portuguese continental slope. The results show an age falsification of 1110-2525 years at sedimentation rates of 10-20 cm ka-1. Since Zoophycos burrows are often poorly or not at all visible in fresh cores, all observations of Zoophycos were made on X-ray radiographs. To avoid dating errors of this kind, an X-ray radiograph study prior to sub-sampling is strongly recommended. © 2001 Elsevier Science B.V. All rights reserved.
SDGs
Type
journal article